Ihe Spanish first order gravity net REDORAES was established in 1973
with the measurements made by combined groups from Ihe IGN (Instituto
Geográfico Nacional, Spain) and Ihe DMATC (Defense Mapping Agency
Topographic Center, USA).
The gravity data were processed by DMATC and results were reported to
ING. Since 1974 lo 1977, a scientific cooperation was established between
the IGN and the present Instituto de Astronomía y Geodesia (IAG) which
proceed lo the analysis of the REDGRAES, and the study of the calibration
une and the regional densification trips to get an automatic procedure for
computing the gravity anomalies in Spain and the global study of the Spanish
gravimetry.
Recently these results have been revised lo obtain a data bank of gravity
anomalies to be used, in cooperation with the «Instituto di Topografía,
Fotogrammetria e Geofísica» (Milano), in Ihe gravimetric geoid determination.
As results of this analysis possible errors in Ihe fírst computation and the lack
of a statistical analysis have been detected. So, a new adjustment of the
Spanish gravity net has been planned using the IGSN 71 stations sited in
Spain.